Many U.S. patents have disclosed provisions intended to prevent slipping on icy surfaces and the like, including the following:
U.S. Pat. No. 281,209 to S. M. Street, 7-10-82, showed a wire-strung shoe sole designed as an anti-wear device;
U.S. Pat. No. 2,494,692 to W. S. Craven, 1-17-50 showed detachable anti-slip equipment for a shoe;
U.S. Pat. No. 3,258,859 to J. F. Lamont and T. P. Gormley, 7-5-66, showed a grid in a shoe heel of plastic;
U.S. Pat. No. 3,574,155 to W. A. Mitchell, 3-30-71, showed a soft rubber sole impregnated with metallic particle;
U.S. Pat. No. 3,597,863 to M. L. Austin, 8-10-71, showed a sole with screen reinforcement inside.